Cabinet Minister Barnaby Joyce has spoken out against Prime Minister Tony Abbott's decision to award the nation's highest honour to the Duke of Edinburgh, arguing it should be reserved for Australians.

A string of Federal Government frontbenchers are defending the Prime Minister's "captain's call" to award Prince Philip a knighthood.

But Mr Abbott's move, revealed on Australia Day, has also puzzled and angered many of his colleagues who were keen for the Government to start the year on the front foot.

A number of Government MPs have publicly raised concerns, arguing there are many Australians who are more deserving.

Mr Joyce said Prince Phillip had contributed to Australia through the Duke of Edinburgh's Award but he would not give him Australia's top honour.

"I'm always of the strong belief that all awards should be for Australians," he said.

Mr Andrews said there was a precedent for giving the award to people outside Australia and said the criticism was "lacking the generosity for which we Australians are famed".

"It doesn't cost us anything to give him this award," he said.

"How else do we say, in a sense, thank you to someone who's given six decades of public service?"

Frontbench senator Michaelia Cash described Prince Philip as "extremely deserving" in terms of the contribution he has made through schemes like the Duke of Edinburgh's award.

But on Tuesday morning senior minister Mathias Cormann dodged questions about whether the Prime Minister made the appropriate decision.

"I'm not a commentator. That was a decision that was made by the Prime Minister," he told the AM program.

"Prince Philip has made a significant contribution in Australia. He's made a significant contribution in particular to the Duke of Edinburgh award, to the lives of hundreds of thousands of young Australians."

Coalition MP Ewen Jones said he agreed governors-general could be eligible to be made knights or dames, but not British royals.

"I didn't believe it," he said.

"I thought of all the things we could do on Australia Day ... Townsville's citizen of the year was a 50-year volunteer of the Girl Guides. I think there's a lot more for Australia that she's done than Prince Philip."

Another MP was more forthright, saying the announcement took the edge off what could have been a good message for Australia Day and showed the Prime Minister's misunderstanding of where Australia is at.

The MP said it was "a stupid announcement" and "manifestly amazing in the worst possible way".

He said "it just adds to the downward spiral" because, while MPs are giving their "unswerving support" to Mr Abbott, "he comes up with Prince Philip".

A second Queensland MP, Warren Entsch, said "for the life of me, I can't understand why" Mr Abbott decided to honour a British royal.

Another MP said "everyone's scratching their heads" at "another error of judgment", adding tongue-in-cheek that it was appropriate in the centenary of Gallipoli for the Prime Minister to keep blowing the whistle, ordering troops to keep going over the top "only to face certain annihilation".

"Beyond ridiculous" was yet another Coalition response.

Immigration Minister Peter Dutton was not prepared to defend the knighthood on Fairfax Radio on Tuesday.

"He made a call there that obviously not all Australians will agree with," he said.

"It's a good quality in people to have passion and to really fight strongly, say what you believe and stand by your convictions, and I think that's what we see in the Prime Minister."

Independent senator Nick Xenophon said Prince Philip already had "every title under the sun".